USP7 and breast cancer: For example, Zhuang et al. found that circ-0100519 enhances the interaction between the deubiquitinating enzyme ubiquitin-specific protease 7 (USP7) and nuclear factor-like 2 (NRF2) in macrophages, promoting USP7-mediated deubiquitination of NRF2, which induces M2 macrophage polarization and promotes breast cancer progression [63].